If you're in Tokyo, you should try the traditional "Kanto-style" oden, because it is really different from the Kansai-style.
Darn! Now you've set me up with the challenge of finding and trying "Kansai-style" oden. I've spent very little time in the Kansai area and it may be years before I get a chance to return there...
Thanks for the Nihonbashi and Ginza suggestions!